Washington: Diplomatic troubleshooter Bill Richardson, visiting Pyongyang to try to ease tensions between North and South Korea, said the situation was "a tinderbox", but urged the North to show restraint and allow contentious military exercises by the South to go ahead.
Richardson said in an interview on CNN he had met with a senior North Korean official and urged "let`s cool things down”.
"I am urging them extreme restraint ... Let`s cool things down. No response. Let the exercises take place," Richardson said.
He said he met on Friday with North Korea`s top nuclear negotiator and was scheduled to hold talks with the head of the military on Saturday.
"I think I made a little headway," he said in a telephone interview with CNN.
He was not in North Korea as an official US negotiator.
"My sense from the North Koreans is they are trying to find ways to tamp this down. Maybe that will continue today, that`s my hope," he said.
"There`s enormous potential for miscalculation," he said.
North Korea said earlier in the day it would strike at the South if a live-fire drill by Seoul on a disputed island went ahead, with an even stronger response than last month`s shelling of the island that killed four people.
North Korean official news agency KCNA issued the threat as South Korea prepared for firing drills on Yeonpyeong island near a disputed maritime border with the North for the first time since November`s exchange of artillery fire.
Richardson suggested the North and South consider holding a summit meeting to discuss ways to avoid an altercation.
"Right now this is a tinderbox. What we need to do right now is not just tamp things down but look at steps that can be taken by the North Koreans, especially such as perhaps allowing the IAEA (International Atomic Energy Agency) to come in and look at the nuclear arsenal."
The United States is working with China, Russia, Japan and South Korea to persuade the reclusive communist state to halt its nuclear weapons programs in exchange for aid and more international recognition.